Cinematograph-film.



J. E. THORNTON.

CINEMATOGRAPH FILM.

APPLICATION FILED 1uLY13hx914.

lntvnted May 16, 1916.

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INVENTUR. 7/2 07 l'b WITNESSES.

UNITED STATES PATENT oEEIoE.

JOHN EDWARD THORNTON, OF WEST HAMPSTEAD, LONDON, ENGLAND, ASSIGNOR TOJOHN O'WDEN OBRIEN, OF MANCHESTER, ENGLAND.

CINEMAT'OGBAlPH-FILM.

Specification of Letters Patent.

Patented May 16, 1916.

Application filed July 13, 1914. Serial No. 850,805.

To all whom it may concern:

Be it known that I, JOHN EDWARD THORN- TON, a British subject, residingat West Hampstead, London, England, have invented certain new and usefulImprovements in Cinematograph-Films, of which the following isaspecification.

his invention provides a means of producing transparent film tapes ofprinted cinematograph pictures in unlimited length at a much cheaperprice than can be produced by the methods now in common everyday use.

Cinematograph picture films are now gen- 4 erally made by taking atransparent, waterproof, and comparatively inextensible material, suchas celluloid, cellulose nitrate, or cellulose acetate, of about 5/1000inch thick, for a base and coating thereon a layer of sensitivegelatino-bromid emulsion, which when dry, is about 1/1000 inch extrathickness. This film is perforated near its two edges, and then printed,developed, fixed, Washed, and dried by the usual well-known methods.During these operations, it shrinks longitudinally somewhat. Thecellulose materials comprising the base are very expensive, andconstitute the main cost of the complete sensitized film. But it isnecessary to use these cellulose materials because they are the onlysatisfactory transparent medium at present known that are suflicientlywaterproof to stand the various developing, fixing, and washingoperations, and at the same time capable of properly supporting thedelicate gelatino-bromid emulsion during treatment therein, withouteither unduly stretching, getting out of shape or crinkling up duringdrying, or falling to pieces while wet. And moreover, they are the onlyknown transparent waterproof materials which are pure enough to have nodeleterious action upon the delicate, highly sensitive emulsion.Celluloid and other nitrate forms of cellulose are expensive enough, andhave the disadvanta e of great flammability; while the acetate orms ofcellulose, though less inflammable, are still more expensive.

In this invention I use for the base of the finished cinematograph filman old wellknown photographic material, but in an entirely new way. Isubstitute for the expensive but inexpensive waterproof cellulose base,one which is non-waterproof, and therefore is expansible, but which isvery cheap (as compared with acetate or nitrate cellulose) yet isentirely fire-proof, its degree of non-inflammability, under theconditions that cinematographic films are used, being far in advance ofthe so-called non-inflamable cellulose acetate films. This material is anon-waterproof colloid or colloids, of which gelatin may be taken as atype to illustrate the principle. I do not, however, confine myselfentirely to gelatin, for other colloids, or similar substances may beused, or even mixtures of two or more, including such as gelatin, glue,Iceland moss, agaragar, alginatos chrondin, albumin and the like. Noneof these colloids is any use as a base for cinematographic films when required to be sensitized, developed, washed and dried in the usual way.But using them in the way hereinafter described they are eminentlysatisfactory.

In describing the methods of carrying the invention into practice I willuse the term gelatin as covering any one or any combination of theaforesaid absorbent colloids or substances, and especially as gelatin'alone is a very suitable colloid on account of its high degree ofpurity, transparency and strength.

The use of gelatin and some other colloids as a support for sensitiveemulsion is very old, it having been proposed over and over again as asuitable support, and in fact such sensitized films have beenextensively offered for saleto photographers, for ordinary pictures,only to be subsequently withdrawn or abandoned asuncommercial. In addition to that it has been proposed to use of film could be dried flatby resorting to many troublesome and lengthy operations, with the greatlengths of narrow film tape required in cinematography the dryingpresented an insurmountable commercial difficulty, and the alteration insize by expansion and shrinkage presented a further difficulty that hasnever yet been commercially overcome. The foregoing description of theart to-day will therefore better illustrate the important further stepof improvement accomplished by this invention.

The present invention is capable of being carried out by the aid ofapparatus of different kinds. In the accompanying drawing, the apparatusis shown diagrammatically, wherein Figure 1 is a perspective view, andFig. 2 is a corresponding longitudinal section through the componentparts of the film and the means employed for uniting the same.

In carrying the invention into practice, I adopt the simple principle ofkeeping the sensitized film B and its transparent support C separatedurin manufacture, bringing them together to %0rm one complete wholeonly after the picture has been completed that is, printed, developed,fixed, washed and dried.

The two component parts of the finished film picture-that is to say, thetransparent non-waterproof and absorbent colloid base, and thenon-waterproof gelatin-br omid (or other form of) sensitive films-may beformed, coated, or cast upon non-extensible surfaces, or temporarysupports upon which they remain until dry. The thick gelatin base mayremain upon its temporary support until the two parts of the film areunited and the support not removed until they are dry, whenmanufacturing the gelatin base in narrow widths, or when manufacturingit in wide widths it is removed from its support when dry and slit upinto strips of narrow width to be subsequently affixed to the printedfilm. The sensitized film B remains upon its temporary support Auntil-it has been printed, developed, fixed I and washed and until thegelatin base or backing C has been attached and the combined film dried.The said non-extensible surfaces or temporary supports are preferablystrips of polished metal A, though polished waterproof paper, celluloid,or other suitable materials may be used.

The manufacturing advantages of this system are.(1) The layer ofsensitized film is so thin that it is very easily and readily developed,fixed, washed and dried. (2) None of the chemicals or water used inthese operations come into contact with the base; therefore it absorbsnothing and there is nothing to be washed out (as has been the case inall previous films where the sensitive emulsion and gelatin support arecombined by the film manufacturer for subsequent use by thephotographer.) (3) A cheap gelatin support can beemployed because it isnot treated with Water, and the sensitive gelatin emulsion cannot expandlongitudinally or laterally during any of the operations, the onlyexpansion which can take place consisting of-swelling in a vertical direction. This is due to the fact that it is held in face-contact withthe non-extensible support A during all operations.

After the sensitive film B has been converted into a series of finishedpictures, the support or backing of transparent colloid C is appliedthereto. The picture may be wet and the backing dry, or vice versa, oneor other being first coated with a substratum of the usual adhesivecharacter as well known to those versed in the art, and then dried. Itis suflicient to slightly moisten one or the other, or both surfaces,such as by passing through a steam box, or under a fine spray of water,and then squeeze them into contact by rolling pressure, and finallyallowing them to dry spontaneously. Or, if preferred, they may be passedtogether through a water trough, and squeezed into contact by rolls D,D, while under the surface of water, to prevent all possibility of airbubbles being inclosed between the united surfaces.

The coating or casting of the two films may be done by any of thewell-known methods; and drying is done in drying chambers supplied withfiltered air at the right temperature in sufficient volume to dry the'united films at the right speed. These'are all matters well understoodby those skilled in the art .of film manufacture upon a large scale, andform no material partof this invention.

The picture film may extend the full width of the base film (when bothare trimmed to correct finished width), but I find it more convenient toform the picture film of a narrow width, so as to just fill up the spacebetween the two lines of perforations, instead of extending over andcovering them.

The base film may be hardened by any of the substances generally usedfor that purpose, such as chrome alum, formalin, or the like, either byincorporating them with the gelatin base before it is cast, or bypassing it through a solution thereof after casting and before drying;or even after drying, which involves re-drying but possesses certainadvantages.

As already stated, mixtures of different colloids may be used instead ofor in addition to gelatin, in order to secure strength, cheapness orother advantages. And suitable substances for securing flexibility mayalso be added, such as sugar, glycerin, or

molasses; also any salts that will render it more fire resisting such asborates, silicates or similar substances. Also in order to secureincreased strength with decreased absorption, and yet still retain themain features of a non-waterproof colloid base, the gelatin may haveincorporated therewith a small proportion of the fibrous solublecelluloseeither nitrate or acetate (but preferably acetate)which can beeasily incorporated in such manner as to not materially affect thedistinguishing qualities or transparency of the colloid base. Themethods of eflectin such mixtures are well known.

Althoug I have described this invention as being carried out withgelatin-bromid emulsion as the sensitive medium (because that is thetype in almost universal use for cinematograph films to-day), it will beobvious that it may be used in conjunction with any other desiredprinting medium, such as the so-called gaslight emulsions, containingsilver chlorid, bichromated gelatin processes, such as the carbon, orpigment or powder processes; mordanted dye processes; or any other thatmay be considered suitable for use for cinematographic pictures.

After the two films have become united and absolutely dry they arestripped, as one complete film E, from the polished temporary support,and may then be trimmed if necessary, as well as perforated or otherwisefinished; and may also be varnished with waterproof varnish (ofcelluloid, cellulose acetate, or other material in suitable solvents) toincrease durability.

The manufacturing process and constructions described may be applied tothe production of films in one color, or to films in several colors(known as natural color films) as described in several other patentapplications of mine dealing with various types of color films.

What I claim as my invention and desire to protect by Letters Patentis 1. The process of manufacturing printed cinematograph picture filmswhich consists in preparing a transparent strip of non-sensitizedgelatin or other similar colloid or substance (either with or without aninextensible temporary support) and a transparent strip of sensitizedemulsion mounted on an inextensible temporary support (transparent oropaque) printing, developing, fixing and washing the sensitive filmwhile mounted on its inextensible support, subsequently applying to theprinted. film the gelatin or other transparent absorbent strip to form apermanent base and finally stripping the completed film when dry fromthe temporary support substantially as described 2. A process forproducing printed cinematograph picture films consisting in attaching acontinuous thick non-waterproof colloid base to an infinitesimally thinprinted image on an indestructible support after the latter has beendeveloped, fixed and washed, and while still wet drying the two inunison while still on the temporary support and stripping the combinedfilm from the support when dry substantiallv as described.

3. As a new article of manufacture, a noninflammable transparentcinematograph film for projection purposes, comprising a thick base orfilm strip composed of a colloid or mixture of colloids ofnon-waterproof character, such as gelatin, glue, agar-agar, albumin, orthe like water-absorbing mate-, rials, having a series of perforationsfor moving it through a projector or lantern, and bearing attached orcemented to its surface another layer of exceeding thinness, comprisinga series of photographically produced images that have passed throughthe usual operations of printing, developing, and washing while mountedupon another ternporary support, from which it is afterward transferred,while in a damp or tacky condition, to the dry film strip of colloidduring the process of manufacture, the two together fonning thefinished'picture film.

4. As a new article of manufacture, a noninflammable strip of continuoustransparent cinematograph film for projection purposes, which isnon-sensitized and is composed of non-waterproof colloids, and istherefore quite unsuitable for subjecting to the usual developing orwater baths, and bearing on one or both faces a series of picturesfirmly cemented thereto, the said pictures being photographicallyproduced .upon a separate exceedingly thin film or Wafer of sensitizedmaterial Which is printed, developed, and washed while attached to atemporary support, from which it is afterward transferred and cementedto the aforesaid thick, nonwaterproof, non-inflammable, permanentsupport which forms the base, the two together forming the finishedpicture film.

5. A printed cinematograph picturefilm comprising a thin printed andfinished strip of emulsion with pictures printed thereon,

and a continuous thick base of a strip of I cheap absorbentnon-flammable colloid which has not received any developing, fixing, orwashing treatment.

6. A printed cinematograph picture film built up of a printed andfinished strip of emulsion which has been printed, developed, fixed andWashed, and a continuous basestrip of gelatin not treated withdeveloping, fixing and washing solutions.

7. A printed cinematograph picture film built up of a printed strip ofsensitized gelatin which has first been printed, developed, fixed andwashed upon an inextensible support, and a continuous base of a cheapabsorbent non-flammable colloid substance to which the printed strip hasbeen transferred and caused to adhere after being finished, the compoundfilm being subsequently furnished with perforations for moving itthrough a projecting apparatus or lantern, substantially as described.

8. A printed cinematograph picture film built up of two layers afterprinting, one being a finished printed picture strip, and the other anon-treated, absorbent, non-fiam mable gelatin colloid strip caused toadhere thereto.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

JOHN EDWARD THORNTON.

Witnesses:

CHARLES E. TAYLOR, DORA H. GIBSON.

